How much of JEE Main comes from Chemical Bonding and Molecular Structure?

JEEGenie estimates about 5% of JEE Main marks come from Chemical Bonding and Molecular Structure, based on recent papers. The share varies from year to year.

Which formulas matter most in Chemical Bonding and Molecular Structure?

The Chemical Bonding and Molecular Structure sheet on this page has 5 formula entries, starting with Bond Order, Formal Charge, Bond Length and Bond Energy, Dipole Moment, Bond Order Calculation from MOT. Each one comes with when to use it and the trap to avoid.

What topics does Chemical Bonding and Molecular Structure cover for JEE?

Chemical Bonding and Molecular Structure covers Ionic and Covalent Bonding, VSEPR Theory, Hybridisation, Molecular Orbital Theory, Dipole Moment, Hydrogen Bonding.

How should I revise Chemical Bonding and Molecular Structure before the exam?

Learn each formula together with its condition of use, read the trap listed beside it, then practise questions and review every mistake. The practice link on this page opens Chemical Bonding and Molecular Structure questions on JEEGenie.

How many previous-year questions are there on Chemical Bonding and Molecular Structure?

JEEGenie has 455 previous-year questions on Chemical Bonding and Molecular Structure, and this page shows a few with worked explanations.

Is practice on Chemical Bonding and Molecular Structure free on JEEGenie?

Sign-up is free and includes a 7-day Pro trial. After the trial, free accounts keep a limited daily quota.

Chemical Bonding and Molecular Structure for JEE Main & Advanced — formulas, what is asked, and traps

JEEGenie estimates about 5% of JEE Main marks come from Chemical Bonding and Molecular Structure. This page covers 5 formula entries, each with when to use it, what JEE asks and the traps. A common slip: Ionic bonds are non-directional, not directional like covalent bonds.

Key points to know

Octet Rule. Atoms tend to achieve a stable noble gas configuration (8 electrons in valence shell) by gaining, losing, or sharing electrons.
Electrovalent (Ionic) Bond. Complete transfer of one or more electrons from a metal to a non-metal, forming cations and anions held by electrostatic force.
Covalent Bond. Sharing of electron pairs between atoms to achieve stable configuration; bond strength depends on overlap and bond order.
Coordinate Bond. A covalent bond where both shared electrons are donated by one atom (donor) to an acceptor with an empty orbital.
Formal Charge. Charge assigned to an atom in a molecule assuming equal sharing of bonding electrons; helps choose the most stable Lewis structure.
Resonance. Delocalization of electrons over multiple atoms, represented by multiple Lewis structures (canonical forms); actual structure is a hybrid with lower energy.
Hybridization. Mixing of atomic orbitals to form new hybrid orbitals with equivalent energy and shape, explaining molecular geometry.
Electronegativity. Tendency of an atom to attract shared electrons in a bond; increases across a period, decreases down a group.
Polarity of Bonds and Molecules. Bond polarity arises from electronegativity difference; molecular polarity depends on vector sum of bond dipoles and symmetry.
Fajan's Rules. Covalent character in ionic compounds increases with small cation size, large anion size, and high charge on ions.
Molecular Orbital Theory (MOT). Atomic orbitals combine to form molecular orbitals (bonding and antibonding); electrons fill according to Aufbau, Hund's rule, and Pauli principle.
Hydrogen Bonding. Attractive interaction between a hydrogen atom bonded to a highly electronegative atom (F, O, N) and another electronegative atom with a lone pair.
Van der Waals Forces. Weak intermolecular forces including London dispersion (instantaneous dipole), dipole-dipole, and dipole-induced dipole interactions.
Sigma and Pi Bonds. Sigma bond: head-on overlap along internuclear axis (stronger). Pi bond: side-on overlap above and below axis (weaker, restricts rotation).
Bond Parameters. Key parameters: bond length, bond angle, bond energy, bond order, and dipole moment; they define molecular structure and properties.
Isoelectronic Species. Species with the same number of electrons; they often have similar structures and properties.

Formula sheet

Name	Formula	When to use
Bond Order	$Bond Order = \frac{N_{b} - N_{a}}{2}$	Predicting bond strength, bond length, and magnetic properties of diatomic molecules.
Formal Charge	$Formal Charge = V - L - \frac{B}{2}$ where V = valence electrons, L = lone pair electrons, B = bonding electrons	Evaluating resonance structures and determining the most plausible Lewis structure.
Bond Length and Bond Energy	Bond length decreases and bond energy increases with increasing bond order (qualitative trend, not strict proportionality) for the same pair of atoms.	Comparing bond strengths and lengths in molecules.
Dipole Moment	$μ = q \times d$	Determining molecular symmetry and polarity.
Bond Order Calculation from MOT	$Bond Order = \frac{N_{b} - N_{a}}{2}$	Predicting bond strength and magnetic behavior of diatomic molecules.

Open the Chemical Bonding and Molecular Structure formula page

What JEE asks

Octet Rule. JEE often asks to identify exceptions (e.g., BF3, SF6, PCl5) or count total valence electrons.
Electrovalent (Ionic) Bond. JEE asks to predict ionic or covalent nature based on electronegativity difference and Fajan's rules.
Covalent Bond. JEE often tests bond order calculation and comparison (e.g., N2 vs O2).
Coordinate Bond. JEE asks to identify donor-acceptor pairs or count coordinate bonds in molecules like H3O+ or NH4+.
Bond Order. JEE frequently asks to calculate bond order for O2, N2, CO, NO, etc., and compare stability.
Lewis Dot Structure Drawing. JEE asks to draw Lewis structures for molecules like SO2, CO2, NO2, and identify resonance structures.
Formal Charge. JEE asks to calculate formal charges in molecules like SO4^2- or NO3^- to identify major contributor.
Resonance. JEE asks to draw resonance structures for molecules like CO3^2-, NO2, and compare stability.
VSEPR Theory. JEE asks to predict geometry and bond angles for molecules like NH3, H2O, SF4, ClF3.
Hybridization. JEE asks to determine hybridization of central atom in molecules like XeF4, SF6, and predict geometry.
Bond Length and Bond Energy. JEE asks to arrange bonds in order of increasing length/energy (e.g., N≡N vs N=N).
Electronegativity. JEE asks to compare electronegativity of elements (e.g., O vs Cl) or use to determine bond type.
Polarity of Bonds and Molecules. JEE asks to identify polar vs nonpolar molecules (e.g., BF3 vs NH3) or compare dipole moments.
Dipole Moment. JEE asks to calculate or compare dipole moments (e.g., NH3 vs NF3).
Fajan's Rules. JEE asks to compare covalent character in halides (e.g., LiI vs LiF).
Molecular Orbital Theory (MOT). JEE asks to write MO configuration for O2, N2, CO, NO and determine paramagnetism.
Bond Order Calculation from MOT. JEE asks to calculate bond order for O2^2-, N2^+, etc., and compare with neutral.
Hydrogen Bonding. JEE asks to compare boiling points (e.g., H2O vs H2S) or identify H-bonding in molecules.
Van der Waals Forces. JEE asks to compare boiling points of noble gases or halogens based on size.
Sigma and Pi Bonds. JEE asks to count sigma and pi bonds in molecules like C2H2, C6H6.
Bond Parameters. JEE asks to arrange molecules by bond angle or bond length (e.g., CH4, NH3, H2O).
Predicting Molecular Geometry Using VSEPR. JEE asks to predict shape of molecules like XeF2 (linear), ClF3 (T-shaped), SF4 (see-saw).
Isoelectronic Species. JEE asks to identify isoelectronic pairs (e.g., CO and N2) or compare properties.

Common traps

Do not apply octet rule to elements beyond period 2 (e.g., P, S, Cl can expand octet). Octet Rule
Ionic bonds are non-directional, not directional like covalent bonds. Electrovalent (Ionic) Bond
A single bond is a sigma bond; multiple bonds have one sigma and one or two pi bonds. Covalent Bond
Coordinate bonds are not weaker than normal covalent bonds; they are equally strong. Coordinate Bond
Bond order can be fractional (e.g., H2+ has bond order 0.5). Bond Order
Do not forget to check formal charge; minimize formal charges for stability. Lewis Dot Structure Drawing
Formal charge is not the actual charge; it's a bookkeeping tool. Formal Charge
Resonance structures are not in equilibrium; they are hypothetical. Resonance
Lone pair-lone pair repulsion > lone pair-bond pair > bond pair-bond pair. VSEPR Theory
Hybridization is a theoretical concept, not a physical process. Hybridization
Bond length decreases with increasing bond order (e.g., C≡C < C=C < C-C). Bond Length and Bond Energy
Electronegativity is not the same as electron affinity (energy released on gaining electron). Electronegativity
A molecule with polar bonds can be nonpolar if symmetric (e.g., CO2, CCl4). Polarity of Bonds and Molecules
Dipole moment is a vector; add bond dipoles vectorially. Dipole Moment

Topics in Chemical Bonding and Molecular Structure

Ionic and Covalent Bonding
VSEPR Theory
Hybridisation
Molecular Orbital Theory
Dipole Moment
Hydrogen Bonding

Previous-year questions on Chemical Bonding and Molecular Structure

JEEGenie has 455 previous-year questions on Chemical Bonding and Molecular Structure. A few worked examples follow.

Year	Questions
2026	23
2025	21
2024	54
2023	39
2022	31
2021	32
2020	22
2019	25
2018	15
2017	15
2016	7
2015	11
2014	17
2013	16
2012	10
2011	3
2010	5
2009	3
2008	3
2007	8
2006	3
2005	3
2004	13
2003	7
2002	9
2001	2
2000	3
1999	3
1998	2
1997	9
1996	4
1995	1
1994	1
1993	3
1992	3
1991	1
1990	3
1989	2
1988	3
1987	3
1986	3
1985	1
1984	1
1983	4
1982	3
1981	4
1979	1

Question 1 medium

Among

{S O}_{2}, {N F}_{3}, {N H}_{3}, {X e F}_{2}, {C l F}_{3}

and

{S F}_{4}

, the hybridization of the molecule with nonzero dipole moment and highest number of lone-pairs of electrons on the central atom is

${s p}^{3}$
${d s p}^{2}$
${s p}^{3} d^{2}$
${s p}^{3} d$

Answer: D

Explanation. First, identify the molecules with nonzero dipole moment. -

S O_{2}

: bent, polar. -

N F_{3}

: trigonal pyramidal, polar. -

N H_{3}

: trigonal pyramidal, polar. -

X e F_{2}

: linear, nonpolar. -

C l F_{3}

: T-shaped, polar. -

S F_{4}

: see-saw, polar. Now count lone pairs on the central atom: -

S O_{2}

: S has 1 lone pair. -

N F_{3}

: N has 1 lone pair. -

N H_{3}

: N has 1 lone pair. -

C l F_{3}

: Cl has 2 lone pairs. -

S F_{4}

: S has 1 lone pair. The molecule with nonzero dipole moment and the highest number of lone pairs on the central atom is

C l F_{3}

(2 lone pairs). For

C l F_{3}

, steric number

= 3

bond pairs

+ 2

lone pairs

= 5

, so hybridization is

s p^{3} d

. Answer: (D)

From NTA/IIT papers: JEE Main 2025 · 2 Apr Shift 1

Question 2 medium

The number of species from the following which have square pyramidal structure is _________

{P F}_{5}, {B r F}_{4}^{-}, {I F}_{5}, {B r F}_{5}, {X e O F}_{4}, {I C l}_{4}^{-}

Answer: 3

Explanation. Use VSEPR theory: count

σ

-bond pairs (bp) and lone pairs (lp) on the central atom; a square pyramidal shape needs 5 bp and 1 lp (steric number 6,

s p^{3} d^{2}

). -

P F_{5}

: 5 bp, 0 lp

\to

trigonal bipyramidal. Not square pyramidal. -

B r F_{4}^{-}

: Br has 7+1=8 electrons; 4 bp, 2 lp

\to

square planar. Not square pyramidal. -

I F_{5}

: I has 7 electrons; 5 bp, 1 lp

\to

square pyramidal. ✓ -

B r F_{5}

: Br has 7 electrons; 5 bp, 1 lp

\to

square pyramidal. ✓ -

X e O F_{4}

: Xe has 8 electrons; 4 bp (to F) + 1 bp (to O) = 5 bp, 1 lp

\to

square pyramidal. ✓ -

I C l_{4}^{-}

: I has 7+1=8 electrons; 4 bp, 2 lp

\to

square planar. Not square pyramidal. Species with square pyramidal structure:

I F_{5}

B r F_{5}

X e O F_{4}

— three in total. The others are either trigonal bipyramidal or square planar. Answer: 3

From NTA/IIT papers: JEE Main 2023 · 6 Apr Shift 1

Frequently asked questions

How much of JEE Main comes from Chemical Bonding and Molecular Structure?: JEEGenie estimates about 5% of JEE Main marks come from Chemical Bonding and Molecular Structure, based on recent papers. The share varies from year to year.
Which formulas matter most in Chemical Bonding and Molecular Structure?: The Chemical Bonding and Molecular Structure sheet on this page has 5 formula entries, starting with Bond Order, Formal Charge, Bond Length and Bond Energy, Dipole Moment, Bond Order Calculation from MOT. Each one comes with when to use it and the trap to avoid.
What topics does Chemical Bonding and Molecular Structure cover for JEE?: Chemical Bonding and Molecular Structure covers Ionic and Covalent Bonding, VSEPR Theory, Hybridisation, Molecular Orbital Theory, Dipole Moment, Hydrogen Bonding.
How should I revise Chemical Bonding and Molecular Structure before the exam?: Learn each formula together with its condition of use, read the trap listed beside it, then practise questions and review every mistake. The practice link on this page opens Chemical Bonding and Molecular Structure questions on JEEGenie.
How many previous-year questions are there on Chemical Bonding and Molecular Structure?: JEEGenie has 455 previous-year questions on Chemical Bonding and Molecular Structure, and this page shows a few with worked explanations.
Is practice on Chemical Bonding and Molecular Structure free on JEEGenie?: Sign-up is free and includes a 7-day Pro trial. After the trial, free accounts keep a limited daily quota.